com.arsdigita.util
Class ConcurrentDict

java.lang.Object
  com.arsdigita.util.ConcurrentDict

public final class ConcurrentDict

extends Object

This class allows you to intern objects in an efficient, thread-safe manner.

The classic example of interning is String.intern(). Interning confers two benefits:

• Reduced memory footprint.

  Instead of having multiple equal instances of an object scattered around in your application, you can use a single instance.

• Faster equality comparison

  If you know you are dealing with interned instances, you can compare them for equality using the == operator rather than the Object.equals(Object) method.

Note: using this class may cause a deadlock, if the methods get(Object) and ConcurrentDict.EntrySupplier.supply(Object) are mutually recursive. Please examine the implementation before using this class.

Since:

2004-02-20

Version:

$Revision: #3 $ $DateTime: 2004/04/07 16:07:11 $

Author:

Vadim Nasardinov (vadimn@redhat.com)

Nested Class Summary

static interface

ConcurrentDict.EntrySupplier

Constructor Summary

ConcurrentDict(ConcurrentDict.EntrySupplier supplier)

Method Summary

Object

get(Object key) Returns the object mapped to this key.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ConcurrentDict

public ConcurrentDict(ConcurrentDict.EntrySupplier supplier)

Throws:

NullPointerException - if supplier is null

Method Detail

get

public Object get(Object key)

Returns the object mapped to this key.

If no object has been mapped to this key yet, this method will call the ConcurrentDict.EntrySupplier.supply(Object) method of the supplier provided to this dictionary at construction time in ConcurrentDict(ConcurrentDict.EntrySupplier).

Note that the null key is always mapped to null.

See Also:

ConcurrentDict.EntrySupplier.supply(Object), ConcurrentDict(ConcurrentDict.EntrySupplier)